The fact is the UK owns Faslane. An independence referendum doesn't change that fact. A yes vote for independence is not a magic spell that will create a Scottish nation and transfer ownership of UK property to it. There will be a lengthy period of negotiation and transition, and whether the Scots like it or not, they will be by far the weaker partner in those negotiations.

then it will remain part of the UK

the nationalists have absolutely no leverage over the UK

if you thought the Brexit negotiations were one sided: you've seen nothing yet